Electrical control assemblage



Aug. 24, 1954 E. L. RUCKS ETAL ELECTRICAL CONTROL ASSEMBLAGE Filed NOV. 16, 1951 A TTORA/E'VJ.

Patented Aug. 24, 1954 2,687,498 ELECTRICAL CONTROL ASSEMBLAGE Edward L. Bucks, Pasadena, Calif., and Arthur B. Johnson, Jr., Maywood, Ill., assignors to Furnas Electric Company, Batavia, 111., a corporation of Illinois Application November 16, 1951, Serial No. 256,703 8 Claims. "(01. 317-420) Our invention relates generally to improvements in control systems for electrical equipment, and relates more particularly to improvements in the construction and functioning of electrical control assemblages involving one or more switch units associated with a common casing or station.

The primary object of the present invention is to provide an improved electrical control assemblage comprising one or more simple switch units detachably but firmly mounted in a protective casing within easy reach of an operator.

It has heretofore been proposed to mount a number of compact electric switch units and pilot lights within a common oiltight casing at a control station especially for the purpose of permitting accurate and convenient operation of machine tools and other complex electric systems, but all of these prior assemblages have been relatively objectionable for diverse reasons.

In most of these prior control stations, the switch and pilot light units were either formed of separate parts some of which were rigidly secured to the casing while others were likewise attached to the cover, or the entire units were suspended only from the casing covers. When the units are formed of separable parts firmly secured to the casing and the cover, it is extremely difiicult to properly align the several parts; and when the units are suspended from the cover alone the switches must be wired with the cover removed and disposed at the side of the casing and subsequently confined within the latter by applying the cover thus making inspection of the finally located wires and connections impossible.

It is therefore an important object of our present invention to provide various improvements in such control stations whereby the pilot light and switch units are held loosely in the casing while making the electrical connections and are finally thoroughly concealed and firmly attached to an oiltight casing closure, this object being accomplished by initially supporting the switch and pilot light units upon the bottom of the casing and by finally firmly anchoring them to the cover when it is applied to the housing.

Another important object of this invention is to provide an improved oiltight control station assembly in which compact switch and pilot light units of various types may be readily grouped in various relative positions and firmly held in assembled condition while still being conveniently accessible.

A further important object of the invention is to provide a durable but exceedingly flexible control switch assemblage in which any desired number of single or multiple switch units may be mounted in a sealed casing in a manner whereby a the group may be quickly removed and just as quickly re-installed so as to insure firm supports for all units during normal use.

Still another object of the present invention is to provide an exceedingly simple, compact and durable control switch station which may be utilized for diverse purposes, and various parts of which are interchangeably similar and may therefore be manufactured and assembled at moderate cost.

Another object of the invention is to provide various improvements in electrical control staswitch terminals are made readily accessible and the switch housings are most effectively supported to resist vibration or displacement thereof, this object being accomplished by supporting the switch and pilot light units from the casing bottom and by finally firmly anchoring them to the casing cover when it is applied.

These and other specific objects and advantages of the invention will be apparent from the following detailed description.

A clear conception of the features constituting our present improvement, and of the mode of constructing and of installing control stations embodying the invention, may be had by referring to the drawing accompanying and forming a part of this specification in which like reference characters designate the same or similar parts in the various views.

Fig. l is a top view of a three-switch unit control station with a part of the closure cover broken away and one of the switch units omitted;

Fig. 2 is a central longitudinal section through the station of Fig. 1, but showing the two retained switch units in elevation and one of them disposed at right angles relative to the other;

Fig. 3 is a central transverse section through the same station taken centrally through the middle switch unit but showing the latter partially in elevation;

Fig. 4 is a fragmentary bottom view of the retainer plate and one of the snap rings for holding each switch unit in proper position within the main casing; and

Fig. 5 is a section through the retainer plate and snap ring taken along the irregular line 55 of Fig. 4.

The gist of our invention is the provision of an electrical control station comprising a covered casing having one or more switch units loosely supported upon the bottom of the casing while the connections are being made and which are thereafter firmly held in place by the cover when the latter is applied to seal the switch contact housings within the casing, and while only a few similar pushbutton switch units have been shown as applied to a common main casing and cover, it is not our desire or intent to restrict the invention to stations embodying any specific number or type of switch units except as defined by the claims. It is moreover contemplated that specific descriptive terms employed herein be given the broadest possible interpretation consistent with the disclosure. p

Referring to the drawing, the improved electrical control assemblage shown by way of illustration, comprises in general a main casing 8 provided with an open top normally sealed by a cover 9 having local openings 10 therein; three similar pushbutton switch units each having a base I l clamped within one of the cover openings H3 and also having a pair of similar switch contact housings l2 secured to its base H by means of elongated clamping elements 13 each having an annularly recessed protruding free end Hi; a re tainer plate 15 fastened withinthe main casing 8 and having therein'three holes 16 disposed in axial al'i'nement with the cover openings H1 and an annular series of perforations ll surrounding each hole 16; and a resilient clamping ring l8 secured to the bottom of the plate IS in overlapped relation to the perforations ll of each series.

The main casing 3 is preferably formed of durable metal and may be provided at one or both ends with a threaded outlet opening 20 to which a conduit for the electrical conductors may be sealingly attached, and the casing 8 may be fastened onto a suitable support with the aid of corner screws which are normally concealed by the cover 9. The metal closure cover 9 preferably coacts with an oiltight sealing gasket 22 and may be detachably secured to the casing 8 by rneans of screws 23, and the openings in in the cover 9 are circularand should preferably be spaced apart and located so as to properly position the desired number and size of switch units which are to be located at the station, see Figs. 1, 2 and 3.

The specific type of pushbutton switches shown do not constitute a part of our present invention except as to their association with the main casing 8 and cover 9, and as previously indicated each of these switch units comprises a base H, a pair of contact confining housings l2, and clamping elements is for attaching the housings E2 to their respective bases II. V Each switch base H has an integralflange 25 and a screw threaded outer portion 26 extending through and beyond one of the cover openings Hi and adapted to receive a ring nut 21 for clamping the flange 25 against flexible sealing members 28 so as to insure oiltight attachment of the bases H to the cover 9. Identification plates '29 may also be clamped between the ring nuts 21 and the cover 9, and a pushbutton 39 is slidably confined within a central bore of each base It and is constantly urged outwardly by aspring 3| while its inner end is provided with a disk 32 for limiting its outward movement and for actuating the movable switch contacts when the button 36 is depressed, see Fig. 2. I

Each of the contact confining housings I2 is provided with spaced pairs of fixed contacts 35,-

35 each carrying a. conductor attaching screw 35, and with a concealed movable contact bar 31 adapted to alternately engage the stationary contacts 34, 35 respectively and which is carried by a plunger 38 cooperable with the disk 32 of the adjacent pushbutton 3d. The plungers 38 are constantly urged toward the disks 32 by springs 39, and these plungers and the engageable portions of the fixed and movable contacts of the switch units are confined within their respective housings l2 by removable cover plates in secured to the housings by screws 4|. The two contact confining housings l2 of each switch unit are disposed back to back and may be attached to the adjacent base flange 25 in either of two positions as illustrated in Figs. 1 and 2, with the aid of the fastening elements It, and each housing l2 has an integral semi-cylindrical projection 42 adapted to coact with one of the holes it in the retainer plate 15.

The retainer plate I5 is also formed of metal and is secured to bosses formed integral with the casing 8 by means of screws 45, and besides the holes lBand perforations ll, this plate I5 is provided with integral offset tongues 4'3 and with similarly offset portions M for holding the resilient snap-rings [8 in place, see Fig. 4 and 5. Each of the rings i8 is confined between the plate l5 and three of the tongues it, the central of which is bent to clamp the ring, and each ring has cutwardly projecting ends e3 laterally slidably con fined within oneof the plate portions 4? while each ring also overlapsthe adjacent perforations H as depicted in Fig. l. The annularly recessed ends I i of the housing attaching elements I 3 are insertible through the perforations ll past the rings l3, andafter spreading the rings during such insertion the latter will contract into the element recesses and will firmly frictionally hold the element ends 14 with the corresponding housings M in snug engagement with the plate l5.

When the various parts of the control station have been properly constructed as described, and the assembled retainer plate I5 and snap rings l8 have been fastened within the main casing 8 with the aid of the screws 45, the several switch units having their contact confining housings l2 clamped to their bases H by means of the clamping elements maybe installed as follows. The electric current conductors maybe passed through the casing. opening 2i! either before or after they' have been attached to fixed contacts 34, 35 with the aid of the terminal screws 36; andthe switch contact confining housings l2 may either be initia lly confined within the casing 8 while the conductors are being attached or such attachment may be effectedwhile the switch units are removed from this casing. When the switch contacts 34, 35 have been properly connected in the control system,- the units should be initially in} stalled vithin the casing before the clamping rings 2'5 and cover 9 havebeen applied, causing the recessedends i i of the elements It to coact with the proper holes I? and snap rings H3 of the retainer plate i5, thus temporarily positioning and holding the several units in the open casing 8 so as to permit free inspection and proper distribution of the wires or conductors throughout the casing interior.

After such initial installationof the several units and their conductors has been made, the cover openings l0 may be slipped over the threaded portionszt' of the several bases H and caused to coact with the sealing members 2:8 and gasket 22,- whereupon the cover 9 may be sealingly attached to the casing 8 by means of the v screws 23. The indentification plates 29 should then be properly placed with respect to the bases H and cover S, after which the ring nuts 21 may be screwed onto the threads 26 to hold the plates 29 in place and to sealingly clamp the cover 9 and bases ll against the members 23 and to thereby firmly secure both ends of the units in position relative to the casing 8. Upon release of the screws 23 and of the ring nuts 27, the cover 9 may be freely upwardly removed from the casing 8 so as to permit inspection or changing of the terminal connections while the casing 8 is fixedly mounted at any desired convenient locality with the aid of the screws 2!.

From the foregoing detailed description of the construction of our switch station assemblage, it will be apparent that we have in fact provided various improvements whereby the terminals and conductors of a compact group of switch units and pilot lights are made readily accessible while the units are effectively supported in an oiltight casing from which the cover is quickly removable. While the pushbutton switch units shown herein forming the subject of various other types of pushbutton and selector switches as well as pilot provement to produce a compact control station operable by a single attendant.

The main casing S of the improved assemblage may be mounted in any desired position, and may also be constructed to accommodate any desired number or" switch and pilot light units, and these units may be mounted in various positions relative to their confining cover 9 in order to facilitate attachment of the numerous conductors to the greatest possible extent. The retainer plate l5 and the resilient snap rings I 8 carried thereby provide a non-rigid support for the ends of the elongated switch contact housing l2 remote from the cover 9, without involving difiiculty in attaching the conductors or in inspecting the parts of the switch units. These control station assemblages may be produced at moderate cost and in various sizes for diverse purposes, and have proven highly satisfactory in actual use.

It should be understood that it is not desired to limit this invention to the exact details of construction of the electrical control station herein shown and described, for various modifications within the scope of the appended claims may occur to persons skilled in the art.

We claim:

1. In an electric switch assemblage, a casing having a removable cover normally firmly attached thereto, a switch unit having a base firmly clamped to said cover and a contact carrying portion secured to said base by clamping elements projecting from said portion, a plate carried by said casing remote from said cover, and a snap ring mounted upon said plate and being cooperable with the projecting ends of said clamping elements remote from said base to frictionally hold said unit in any of several selected positions within said casing while said cover is being applied.

2. In an electric switch assemblage, a casing having a detachable cover provided with several local openings, a switch unit adapted to be firmly clamped to said cover at each of said openings, each unit having a base normally secured to the cover at one of said openings and a contact confining housing extending away from its base and clamped thereto by fastening elements having ends of several of said switch units to temporarily hold said housings in position within the casing while said cover is being applied.

each unit having a base secured to the cover at one of said openings and a contact confining housing extending away from its base and clamped thereto by fastening elements having annularly recessed ends projecting rearwardly beyond the adjacent housing, a plate secured within said casing remote from said cover and having perforations for receiving said projecting element ends, and snap rings mounted upon said plate and being cooperable with the recesses of said element ends to initially frictionally hold said housings in predetermined position within the casing before said cover has been applied.

4. In an electric switch assemblage, a casing having a detachable cover provided with several local openings, a switch unit normally positively clamped to said cover at each of said openings, each unit having a base sealingly secured to the cover at one of said openings and a contact confining housing extending away from its base and clamped thereto by fastening elements having annularly recessed ends projecting rearwardly beyond the adjacent housing, a plate secured within said casing remote from said cover and having several sets of perforations for receiving said projecting element ends in variou predetermined positions, and snap rings mounted upon said plate and being cooperable with the recesses of said element ends to frictionally hold said housings in position within the casing before said cover has been applied, each of said housings also having an integral central projection extending into one of said plate perforations.

5. In an electric. switch assemblage, a casing with several cured to said cover at each of said openings, each unit having a base firmly secured to the cover at one of said openings and a pair of back to back contact confining housings clamped to each base by several fastening elements having annularly recessed ends projecting beyond the housings and away from the base, a plate secured within said casing remote from said cover and rations for interchangeably receiving said element projections with said housings disposed in various positions relative to the corresponding cover openings, and snap rings mounted upon said plate and being cooperable with said element end recesses to hold said housings in position while the cover is being applied to the casing.

6. In an electric switch assemblage, a cupshaped casing having a removable closure cover normally attached thereto and being provided with an internal plate disposed remote from said cover and spaced from the casing wall farthest from the cover, a switch unit having a base normally sealingly clamped to said cover and also having a contact housing secured to said base by fastening elements projecting from the housing, and resilient means carried by said plate and being cooperable with the projecting ends of said elements to temporarily frictionally hold said unit shaped casing having 7 within said casing while said cover is being applied.

'7. In an electric switch assemblage, a cupshaped casing having aremovable closure cover provided with several openings and also havin an internal plate disposed parallel to said cover and spaced. from the casing wall farthest from the cover, a switch unit normally sealingly clamped to said cover at each of said openings, each of said switch units having a base and a contact housing secured to its base by fastening elements projecting from its housing and coacting with said plate, and resilient means associated with said plate and being cooperable with said projecting element ends to temporarily frictionally hold said units within said casing while said cover is being applied.

8.31 an electric switch assemblage, a cupa removable closure cover provided with several openings and also having an internal plate disposed parallel to said cover and spaced from the casing wall farthest from the cover, a switch unit normally sealingly clamped to said cover at each of said openings, each of said switch units having a base and a contact housing secured to its base by fastening elements projecting from its housing and coacting with said plate, and a snap ring carried by said plate adjacent to each of said units and being cooperable with the projecting element ends of the adjacent unit to temporarily frictionally hold the latter within said casing while said cover is being applied and fastened to said bases.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,357,973 Robbins Sept. 12, 1944 2,372,083 Johannson et al. Mar. 20, 1945] 2366,5970 Schellman Apr. 12, 1949 2,506,505 Jeffrey May 2, 1950 2,526,901 Robbins Oct. 24, 1950 2,568,933 Robbins Sept. 25, 195i 

